Some commentators say that the world has become more insular as people now walk around with their IPod headphones on, listening to their own music and never interacting with the people around them. I guess I'm one of those insular people (though with an IRiver not an IPod).
Now someone has realised that the IPod screen is just a little too small for watching movies, but with video glasses you can turn it into a 42" virtual screen.
These things been out for years and have never taken off. I used a similar pair a few years ago and wasn't impressed. The screens were not particularly large or clear. Plus I wear glasses and the headset just wasn't designed for use with glasses. I did use a cool IBM concept headset once that allowed the user to view a computer screen on a little clear pane through which you to view the computer screen or the real world depending on how you focused your eyes. I have never seen either of those headsets in the shops since. They were never more than a novelty since there was never an easy enough way to carry the movies and player.
Now with Video IPods there may well be an opportunity. Of course the price would have to come down *alot* and the technology would have to have improved since I used it, but I can easily see teenagers and gadget freaks sitting on busses and trains watching movies on headsets (and missing their stops). You could even produce a IPod Video\3G phone adapter for a headset that could view movies from the IPod and 3G content from the phone.